Thermometer using liquid crystal compositions

ABSTRACT

A thermometer comprising a plurality of temperature responsive sections formed of liquid crystal compositions and which change their color in response to a specific range of prime temperature. Each temperature responsive section in its responsive state produces a different color depending upon temperature within the specific range. The color thus produced can be numerically identified by reading a comparable chromatic pattern.

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154 TEEERMGMETER USENG LEQUED 3,5919% 8/1971 Fryer 73 /358 CR STAL QQMPQSETEQNS OTHER PUBLICA'HGNS [721 Inventors: iiroshi sew; Mime) Ueda, both of Tokyo; Semis Segewa, Saitarnaken, all of Japan {73] Assignee: Sankyo Heiryezi Keeiskiks' Keisha, Prim'ry Examiner-Louis R. Prince i Toizymlapan Assisrent Examiner-Denis E. Corr I [22] Filed: Bea 28 I9? Attorgey George B. Ou eyoi-k Physiesby Hausman and slaek copyright 1935 end 1939 page 622. v I

21 A l. No 101,532 Assess-er A therrnometer comprising a plurality of temperature [52] us. CE ..-....73/356 po s seciions farmed 0f iiqvid crystal p 511 int. c: "sen; 11/16 firms and which change their war in r p w a {58} Fiei ofsearch ..73/356; '23/230'L 252/402 fis range of Prime temperature Each tempcw ture responsive section in its responsive state produces a different coIor depending upon temperature within 56 R Ee n esC'teei I e y s t the specific range. The color thus produced can be nu- UNITED STATES PATENTS mericaily identified by reading a comparable chroi matic pattern. 3,441,513 4/1969 Woodmansec ..23/23O LC 2,932,97! 4/1960 Moore ..73/356 1Caim,2DrawingFigures 4A 6B III- 48 4c -1 2- 3 w u, L) .0 O it 35. 3s s2 -3em nimum HHHIH-IHHH-HHHH 1m do i. o.2. 0.4 0.6 0.8 M 1.0

ERMOMETER USING LlQUID CRYSTAL CQMPGSETIQNS BACKGROUND OF lNVENTlON invention related to a thermometer using tem- 5 perature responsive liquid crystal compositions whose initial color changes responsive to threshold temperatures,

SUMMARY or The niv'eurrou The principal object of this invention is the provision of a thermometer of the type described above, which is not only fast-acting, safe to handle, and light in weight,

f but also readable relativelyto a finely graduated degree.

BRIEF DESCRIPTION OF THE DRAWING PK}. 1 is a plan view of a temperature measuring device embodying this invention with its front cover removeiand Y H FR]. 2 is anenlarged cross section taken along a line li-ll ofFlG. I.

DESCRiPTI'ON or THE PREFERRED EMBoniMeNr.

Referring to FIGS. 1 and 2, the reference numeral 1 indicates a support comprising a base sheet 2 formed of metal, such as aluminum, or synthetic resin, and a front cover- 3 formed of a substantially transparent synthetic resinous material and having dimensions substantially equalto those of the base sheet ZQBetween the base sheet2} and the front cover 3 are arranged a plurality of temperature responsive sections dAQB, 4C formed f liquid crystal compositions. Seven such sections are illustrated in FIG. 1 in alignment with each other with spacings, and accompanied by numerical indications 6A,.6B indicating threshold temperatures at which the temperature responsive sections 4A, 4B, 4C reach.

The te-nperture responsive sections may be termed face of the frontcover 3 men the upper surface of the base. sheet 2 seven different liquid crystal compositions each having a color changing property at predetermined temperatures. Namely, the temperature responsive' section 2A is responsible to a specific range of temperalture or a temperature between 35 and 36 C, the

section ii between 36 and 37* C, the section 4C D between 37 and 38- C and so, forth, so that the thermometer as illustrated may be used to measure a tem peratu rebetween 35 C and 42 C.

responsive section will produce various colors depending upon temperature within the prime temperature 2 range. For example, when the section d A' whose prin temperature range is between 35 to36 C is been first at 35 Cand the temperature is gradually eleven to 3.6 C, it will first be colored red and the color w then change successively from red to orange, yelloi green, light blue, dark blue and purple in the 0rd mentioned. Y i

The thermometer of this invention further comprisi a first strip 8 carrying a chromatic pattern 7 therec and asecond strip it) which bears a graduation 9 wii numerical indications. The first and second strips an It? may be bonded to the surface of the base sheet 1 Alternatively the chromatic pattern.7 and the gradu; tion 9 may bereproduced directly on the base sheet or either side of the front cover 3, for example, b printing.

The chromatic pattern '7 represents a rainbow, lil: pattern including red, orange, yellow, green, sky blue dark blue and purple. These colors correspond to th colors that can be produced by any temperatur responsive section when the temperature to which sail section is subjected falls in its prime temperature range The entire length of the chromatic pattern 7 whicl covers 1 Centigrade is graduated as at 9 so as to in dicate, for example, a fiftieth of a degree. in the em bodirnent shown, the graduation 9 is numbered in step of 01 C, which will practically assist reading of sub stantially a tenth of a degree Centigrade.

in operation, when the device is exposed to an objec whose temperature is to be measured and the temperature responsive section, say 4C, produces a color other than black or different from the other sections, it car he read that the temperature is 37 C or above, but less than 38 C. The specific color produced should then be identified on the chromatic pattern. If the color is orange and the visuall quivalent color in the chromatic pattern is read to be indicated by 0.2 of the graduation, the measuring temperature should be 37.2 C. When the temperature is say exactly 37 C, two adjacentsections, such as sections 48 and 4C will operate to be responsive. in such a case, either one of them may be optionally selected as an operating section, and the color thereof compared with the chromatic pattern.

On the rear surface of the base sheet 2 may be deposited an adhesive film 22 which in turn may be covered with a thin protection sheet 11 made of a material capable of being easily peeled. The adhesive film l2 permits the device to be so positioned as to be properly exposed to an object or a patient whose temperature is to be measured. a

if a reversibietype liquid crystal composition is employed instead of a memory type composition, repeatedly usable thermometers may be provided.

What is claimed is:

l. A thermometer for measuring body temperature, comprising:

a. a support (I) with front and back including an elongated base sheet (2) and a transparent cover (3) over said base sheet on the front; I b. a first strip (8) on said base sheet (2), said base sheet having thereona plurality of temperature responsive sections (3A, 4B, 4C) of cholesteryl crystals, said sections being aligned with spacing therebetween and accompanied by numerical designations.(6A) indicating the threshold temperature at which a particular section reacts;

' c. a fine scale (9) on a second strip (i6) incremented in frcxions of the temperature difference between the response temperatures of adjacent seetions disposed along one side of seid support, said first and second ships (8, E0) being between said'base 5'- sheeflZ) and said cover (3); and, (1. adhesive means on the back side of said support.

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